a) Field of Invention
The present invention relates to a vehicular lamp system, such as a headlamp system, for a vehicle such as an automotive vehicle.
b) Description of Related Art
Each of a Japanese Patent Application First Publication No. Heisei 8-183385 published on Jul. 16, 1996 (which corresponds to a U.S. Pat. No. 5,711,590 issued on Jan. 27, 1998) and a Japanese Patent Application Second (examined) Publication No. Heisei 5-25697 (which corresponds to a Japanese Patent Application First Publication (Unexamined) No. Heisei 2-45234 published on Feb. 15, 1990) exemplifies previously proposed vehicular lamp systems.
In the previously proposed vehicular lamp system disclosed in the former Japanese Patent Application (JP8018385), a reflector is divided into two portions: an upper displaceable (movable) light distribution reflector; and a lower fixed light distribution reflector.
The lower fixed light distribution reflector is designed to reflect 50 to 60% of a total quantity of light applied to the reflector. The upper displaceable light distribution reflector is designed to reflect the remaining percentage of the total quantity of light. During the vehicular turn of a corner, the lower fixed light distribution reflector serves to secure a visibility of a vehicular front lighting area and an upper displaceable light distribution area is pivotally displaced toward a direction of turning so as to radiate the light from a light source onto a vehicular forwarding direction.
On the other hand, in the previously proposed vehicular headlampd is closed in the latter Japanese Patent Application Second Publication, a light radiation direction is continuously varied together with a steering operation of a steering wheel and a gain of a radiation angle of light with respect to a steering angle is fixedly set as 1 to 1.
However, since, in the vehicular headlamp disclosed in the former Japanese Patent Application First Publication, a pivotal control for the upper displaceable light distribution reflector often causes a visibility of surrounding of the vehicle to be insufficient during turn of vehicle on a traffic intersection. Conversely, in order to improve the visibility, an extremely highly responsive pivotal control to the steering operation is carried out. This causes such an abrupt change in the light distribution as if a switch on-and-off control for light were carried out to change a light distribution so that an insufficient feeling is given to a vehicular driver.
Since, in the previously proposed vehicular lamp disclosed in the latter Japanese Patent Application Second Publication, a gain of the lamp radiation angle to angular displacement of steering wheel is set as 1 to 1 so that when a steering wheel is quickly steered, the gain remains unchanged so that a vehicular driver gives insufficient feeling. Hence, there is a limit in improving the visibility without giving the insufficient feeling to the vehicular driver.
It is, hence, an object of the present invention to provide a vehicular lamp system which can improve a visibility both in a front lighting area and in turning direction of the vehicle without giving an insufficient feeling to a vehicular driver even during a run of the vehicle on a traffic intersection.
According to one aspect of the present invention, there is provided a vehicular lamp system, comprising: a displaceable light distribution section that radiates a light from a light source into a predetermined light distribution area and is enabled to displace its light distribution state toward a direction toward which a displacement angle thereof to an optical axis of the light source is formed; a drive section to drive the displaceable light distribution section to displace its light distribution state from the optical axis of the light source by the displacement angle; a steering angle sensor to detect a steering angle of a vehicular steering wheel; and a controller to control drive section to displace the light distribution section by the displacement angle in accordance with a detected value of the steering angle, the controller comprising a gain setting section that sets a gain prescribing the displacement angle with respect to detected value of the steering angle to fall in a predetermined range such as to displace the displaceable light distribution section by a predetermined displacement angle smaller than the detected value of the steering angle.
According to another aspect of the present invention, there is provided a vehicular lamp system, comprising: a displaceable light distribution section that radiates a light from a light source into a predetermined light distribution area and is enabled to displace a light distribution state thereof toward a direction toward which a displacement angle thereof to an optical axis of the light source is formed; a drive section to drive displaceable light distribution section to displace light distribution state from the optical axis of the light source by a displacement angle; a steering angle sensor to detect a steering angle of a vehicular steering wheel; and a controller to control drive section to displace the light distribution section by the displacement angle in accordance with a detected value of steering angle, the controller comprising a gain setting section that sets a gain prescribing the displacement angle of the displaceable light distributing section with respect to a detected value of the steering angle to fall in a predetermined range such as to both of a visibility of the light distribution area and an inverse of a level of insufficient feeling have exceeded predetermined preferable evaluation values in a sensory evaluation test.
This summary of the invention does not necessarily describe all necessary features so that the invention may also be a sub-combination of these described features.